Magnetoresistance of Iodine-Doped CdMnTe/CdMgTe Spin Quantum Wells

Abstract

Single Cd1 xMnxTe quantum wells embedded in nonmagnetic Cd1 yMgyTe barriers were grown by using molecular beam epitaxy (MBE). The Cd1 xMnxTenCd1 yMgyTe structures were modulation doped by using iodine donors. The manganese (x) and the magnesium (y) contents were carefully adjusted to obtain the same values of the energy band gaps in both materials. A composition adjustment was achieved based on photoluminescence measurements. The magnetoresistance measurements were carried out in the temperature range from 1.6 K to 300 K and at magnetic elds up to 9 T. The analysis of the Hall e ect measurements indicated that increasing of the magnetic eld caused the formation of a quantum well in the conduction band of the magnetic Cd1 xMnxTe layer. This e ect caused a transfer of quasi-free electrons from a 3D conducting channel located in the non-magnetic Cd1 yMgyTe barriers to a magnetically-induced 2D quantum well. As expected, the electrons localized in the 2D conduction channel were highly mobile, which was manifested by the appearance of Shubnikov-de Haas oscillations.